Connector plug



March 2, 1943. A. BROWNSTEIN 2,312,794

CONNECTOR PLUG Filed Jan. 5, 1940 Zeal/leaf ATTORNEYS Patented Mar. 2, 1943 s'rEs 7 Claims.

This invention relates to an electrical contact plug, and, more particularly, to a resilient contact plug having blades therein which are adapted-to be readily attached to an electrical conductor to connect the same to an electrical outlet.

Resilient contact plugs have been heretofore devised and, as they are not subject to fracture, have obviated many difiiculties to be found in the molded resin or plastic plug bodies. These plug bodies, furthermore, being resilient and pliable, will permit blades mounted therein to have a slight play to accommodate outlets having a variance between the sockets adapted to receive the blades without injury to the plug.

These prior proposed resilient plugs have been formed generally in two pieces, although single piece resilient plugs have been formed wherein the blades were assembled after the plug had been molded and without the use of screws, rivets or like parts which might work loose during the life of the plug. v

In these previous one piece rubber plugs, it has been difficult t0.securely mount the blades within the plug body against removal so as to insure their permanent connection to the plug body. The contact blades generallywere held within the plug by the resiliency of the plug itself which was distorted when the blades were mounted. When the contact blades were held within the plug in this manner, the blades were generally unsteady due to insuflicient frictional contact with the plug body and oftentimes worked loose.

In the device of the present invention, the blades are assembled by insertion through a cavity formed in the rear of the plug and then into blade slots and are permanently held in the slots by an interlocking engagement between means formed in the blade slots and the blades themselves without distortion of the plug body when the blades are in the assembled position. The blade slots of the present invention are formed with means on the walls thereof which are engaged by means carried by the blade and interlock therewith when the blades are in the proper assembled position. The interlocking means are so formed as to prevent the blade, after the same has been properly assembled within its respective slot, from being removed from the plug body.

This is accomplished in the present invention by forming oppositely directed shoulders adjacent the opposite ends of the blade which engage suitably formed seats on opposite walls of the slot and tangs which project from the face of the blade and lie in a plane at an angle to the plane of the shoulders to engage an undercut shoulder formed on an adjoining wall of the slot. The blades are, therefore, so anchored that movement of the blades, transversely of the slot, to a position where either the tangs or shoulders are out of engagement with their respective elements of the slots, will not permit their removal, as the shoulders and tangs lie in intersecting planes and either the shoulder or tangs will be always effective to hold the blades against longitudinal movement.

To more effectively hold the blade again movement inwardly of the body, each slot, in one form of the invention, terminates at its inner end in a seat upon which the blade rests when in the proper assembled position.

If desired, and to facilitate the molding operation of the plug body, the seats at the inner extremity of the slots may be dispensed with and the wall of the slot made continuous with the wall of the cavity formed in the rear of the plug.

The contact blades in one form of the invention are formed of the relatively inexpensive metal, aluminum, provided with a suitable outer surface of copper, tin or the like. The copper or tin coated aluminum blades reduce the cost of manufacture of the connector plug, but do not impair the efliciency of the same. I

Other features and advantages will hereinafter appear.

In the accompanying drawing:

Figure 1 is a perspective view of the plug with the blades inserted.

Fig. 2 is a vertical section of the plug with the blades removed.

Fig. 3 is a section along line 33 of Fig. 2.

Fig. 4 is a view similar to Fig. 2, but showing the blades in position.

Fig. 5 is a view similar to Fig. 3, but showing a blade in position.

Fig. 6 is a perspective view of the blades as they are positioned in the plug.

Fig. 7 is a view somewhat like Fig. 4, but showing a modified form of my invention. I

Fig. 8 is a section along line 88 of Fig. 7.

Fig. 9 is a sectional view of a blade having its outer surface plated.

The attachment plug of the present invention includes a body ill of some resilient moldable material such as rubber and preferably is made in one piece. It is provided with a pair of blade slots II for receiving and supporting the contact blades l2. When the blades l2 are inserted in the body, the operative portions thereof project from an end l3 of the body. Projecting from the other end of the body is a cable II, the wires l5 of which are connected to the blades through a cavity l3. The cavity I6 is connected to the inner ends of the blade slots H by suitable passageways A suitable shaped lug l3 projects into the cavity l3 and acts to space the wires in the cavity and serves as a guide when the blades areinserted into the blade slots.

According to the present invention, the outer walls 20 of the blades slots H are smooth and uninterrupted so that, when the blade enters the slot, the free end 2| of the blade may slide along this wall without obstruction. I

As shown in Fig. 2, the inner wall 22 of each blade slot is also substantially continuous and the space between the walls 20 and 22 of each silzot is substantially the thickness of the blade Each blade is provided with some anchoring means 23 in the form of an aperture, in the embodiment of the invention herein illustrated, and serves to. more securely hold an end of the wire 15 to the blade so that it may be conveniently soldered thereto.

In assembling the cable and plug, the wires are secured to the blades below the anchoring means. The blades are inserted, with the free ends first, through the .cavity l5 and into the passageways II, which insertion is continued until the blades take the final position in the blade slots II, as shown in Fig. 4, with the free ends projecting for the engagement of contacts in a suitable receptacle.

The present invention provides a means for seating and anchoring each blade within its respective slot and which does not require that the body of the plug, which is of resilient material, be maintained under distortion after the blades are inserted. For this purpose, each blade slot II is restricted, as at24, forming seats 25 and 23 on the walls 21 and 28, respectively, of each blade slot adjacent the end l3 of the plug and seats 23 and 33 adjacent the inner end of each blade slot. Also, the wall 22 of each blade slot is formed, at the jointure with the passageways H, with an undercut shoulder 32.

Each contact blade I2 is cut away, as at 33, to form shoulders 34 and 35, which shoulders, when the blades are properly disposed within the plug body, engage the seats 25 and 26, respectively.

The blades are formed with shoulders for engaging seats 23, 30 by lancing a portion from the marginal edges thereof and bending the lanced portion outwardly. The outwardly bent portions form tangs 33 which engage the undercut shoulders 32 when the blades are properly mounted in the plug body.

It will be seen that, due to the engagement between the shoulders 34 and 35 of the blade with the seats 25 and 23 of each blade slot, longitudinal movement of the blade inwardly of the plug is prevented. To more securelyhold the blade against movement inwardly of the plug, the inner end of each blade rests on a seat 31 formed at the inner extremity of each blad slot.

Longitudinal movement of the c itact blades outwardly of the plug body is prevented by the interlocking engagement of the spaced angularly extending tanks 36, lying in a plane at an angle to the plane of the shoulders 34 and 35, with the undercut shoulder 32, as well as by the engagement between the shoulders 33 and 33 with the seats 23 and 30.

The blades, once assembled, are permanently held within the plug body, for it will be seen that if the blade were to be moved transversely of the slot to a position, for instance, wherein the tangs 33 were no longer in engagement with .the undercut shoulder 32, the blades, nevertheless, could not be removed from the slot due to the engagement between the shoulders 38 and '33 of the blade and the seats 23 and 30 formed held within the slots after they have been in-- serted and cannot be removed unless the plug body is destroyed.

To assemble the cable contacts and plug body. the contact blades, to which the wire ends have been secured, are inserted, free end first, into the cavity l6. Then the blades are passed through the passageways l'l into the slots II, the free end of each blade riding on the smooth outer wall 20. The blades will distort the plug body as they are passing through the restricted portion 24 of each slot, but, as the distance between the seats 25 and 26 and the undercut shoulder 32 is substantially equal to the distance between the shoulders 34 and 35 of the blade and the tangs 36, the body will return to its normal condition after the tangs have entered the undercut shoulder 32 and ,the shoulders 34 and 35 engage the seats 25 and 26 of the blade slot. The resiliency of the body will also incidentally position the inner end of the contact blade on the seat 31 and the blade will be locked in its blade slot.

The contact blades have been described as being mounted by pushing them through the plug body into their respective slots, but it will be understood that suitable tools may be inserted through the slots to pull the blades into their proper position.

In the form of the invention illustrated in Fig. '7, the seat 31 of the previously described form of the invention is dispensed with and the wall 20 of the slot is continuous with the wall of the cavity I1. This form of the invention, although it does as securely hold the blades in their assembled position as the previously described form of the invention, is, nevertheless, more economical to manufacture, as the elimination of the seat makes the molding operation by which the plug body is formed more simple. The seats 31 have not only been dispensed with, but also 'the seats 23 and 30 as well.

The inner extremities of the contact blades, in this embodiment of the invention, are bent inwardly, as viewed in Fig. 7, so that the inner ends lie within the passageways H which eliminate the necessity of the shoulders 29 and 30. The plug is otherwise the same as the plug, as shown in the previous referred to figures, and the blades are assembled in substantially the same manner as are the contact blades of .the previously described form of the invention.

The contact blades may be composed of some suitable metal, such as brass or copper, but, preferably, referring now to Fig. 9, each contact blade is formed as a core 45 of aluminum and is provided with a suitable coating 46, such as brass, copper, zinc, tin or the like. By forming the body of the blade of aluminum and then suitably coating the surface of the aluminum, the cost of manufacture is considerably reduced. The blades may be formed by stamping the same from sheet aluminum forming the shoulders 34 and 35 and the tangs 36, and then, by any suitable coating process, coat the same with the now preferred metals previously mentioned. The blades may be formed by striking the same from an aluminum sheet which has been previously coated, and the ends of the wire which are to be connected to the blades may be suitably tinned so that the copper wire will not contact the alumlnum walls of the aperture 23 when the same is formed.

It has been found that the blades cannot be completely formed of aluminum, for a deleterious action is set up between the aluminum and the copper contact of the receptacle when the plug is connected thereto, and, for this reason, it is necessary to coat at that portion of the contact blade which is to come into contact with the usual copper surface of the receptacle, as well as that portion of the blade to which the bared end of the wire is connected. Applicant has found that considerable savings are effected when the blades are formed as just described.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

1. In an electrical contact plug comprising a resilient body having a pair of spaced blade-positioning slots extending into the same from one face thereof and a single cord receiving cavity opening into the opposite face of the body and communicating with the inner ends of said slots, a portion of two opposing walls of each slot projecting toward each other and forming restricted sections intermediate the ends of each slot; a

blade positioned in each slot, each blade having indented margins coextensive with and conforming to the restricted sections of the slots; and tangs lanced from the margins of each blade and angularly projecting from a face thereof for interlockingly engaging with a notch formed in a wall of each slot other than said first mentioned walls and disposed intermediate the ends thereof, the engagement between said projecting portions and the indentations of said blades and the tangs and notches respectively permanently anchoring said blades in the slots of the body.

2. An electrical contact plug comprising a resilient body having a plurality of blade-receiving slots extending therethrough, said slots having a plurality of seats formed therein, said body having a recess communicating with each slot adjacent one of said seats; and a blade mounted in each slot, said blade having a pair of shoulders formed thereon lying in the plane of the blade for engaging seats in the slot and a pair of tangs lanced therefrom and bent at an angle to the plane of the blade for forming shoulders in the plane of the blade for engaging other seats in the slot, the portion of the tangs projecting beyond the plane of the blade interlockingly engaging the walls of the recess, the shoulders of the blades cooperating with the seats, and the tangs with the walls of the recess to permanently anchor the blades within the slots.

3. In an electrical contact plug comprising a resilient body having a pair of spaced blade-positioning slots extending into the same from one face thereof and a single cord receiving cavity opening into the opposite *face of the body and communicating with the inner ends of said slots; inwardly projecting seats formed on opposite walls of each slot adjacent the open end thereof, each slot terminating in a transversely extending seat at the inner end thereof; a blade mounted in each slot, the inner end of each blade bearing against said transverse seat; a pair of shoulders formed on each blade intermediate the ends thereof engaging the seats formed on the walls of each slot; and a pair of tangs lanced from the margins adjacent the inner end of each blade and angularly projecting from a face thereof, said tangs interlockingly engaging notches formed on a. wall of each slot other than the first mentioned walls and disposed intermediate the ends of said slot and cooperating with the end of each blade and its seat, and the shoulders and the shoulder-engaging seats to permanently anchor each blade within its slot.

4. In an electrical contact plug comprising a resilient body having a pair of spaced blade-positioning slots extending into the same from one face thereof and a single cord receiving cavity opening into the opposite face of the body and communicating with the inner ends of said slots, each slot being widened adjacent the opposite ends thereof to form oppositely facing seats on opposite walls thereof a blade mounted in each slot, each blade being formed intermediate its ends with a narrow portion forming on the opposite margins thereof shoulders engaging the seats of the slot; a pairof angularly projecting lanced out tangs carried by each blade adjacent the in ner end thereof, said tangs interlockingly engaging with an undercut notch formed on a third wall of each slot intermediate the ends thereof, the tang and the notch and the shouldersand the shoulder-engaging seats cooperating to permanently anchor said blades within said slots; and a twin conductor cord extending into said body through said cavity and having each conductor thereof connected to one of said blades.

5. In an electrical contact plug comprising a resilient body having a pair of spaced blade-positioning slots extending into the same from one face thereof and a single cord-receiving cavity opening into the opposite face of the body and communicating with the inner ends of said slots; a fiat blade positioned within each slot; and a pair of oppositely facing shoulders formed on each margin of said blades, each shoulder engaging a seat formed on opposite walls of each slot, at least one of said shoulders being extended to form a. tang angularly projecting from a face of said blade and received within a notch formed on a wall of each slot, the engagement between the shoulders and the tangs with the seats and notches respectively of the slots permanently anchoring the blades in the slots.

6. An electrical contact plug comprising a onepiece resilient body having a pair of spaced blade-receiving slots extending into the same from one face thereof and a cord-receiving cavity opening into the opposite face of the body and communicating with the inner ends of said slots;

and a blade disposed within each slot, the opposite walls of each slot projecting toward each other to form a pair of seats at opposite ends of each slot, the opposite margins of each blade being cut away to form a pair of spaced shoulders adjacent the opposite ends thereof, a part of the cut away portion of each blade being bent over to form a pair of tangs projecting from the one face thereof, one of the walls of each slot not formed with said seats having at least one undercut notch for receiving the tangs of each blade,

each having an insulated electric conductor secured thereto, said contact blades being simultaneously insertable through the cavity into said slots after said conductors are connected to the respective blades, each blade having spaced angular extending tangs formed thereon and a pair of shoulders formed on opposite margins of said blades and facing said tangs, the base of said tangs forming shoulders facing the first-named shoulders, the opposite walls of each slot projecting toward each other to form a pair of seats at opposite ends of each slot; and a wall other than said named walls being formed with notches for receiving the tangs of the blades, the shoulders of the blades engaging the seats of the walls and cooperating with the tangs received within said notches for permanently anchoring the blades in the slots.

ARTHUR BROWNSTEIN. 

